Apparatus and method for supporting mobility of wireless terminal in wireless communication network

ABSTRACT

A method and apparatus for informing terminals in a UMTS regarding state information of an MBMS in order to prevent terminals from requesting a service that cannot be provided in a cell in which it is newly located. The mobile communication network informs the terminals about its service provision state for a particular MBMS service being provided, and the terminals operate in accordance with this service provision state information to minimize unnecessary operations of the terminal and unnecessary signaling and waste of radio resources.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/845,204, filed May 12, 2004, now U.S. Pat. No. 7,349,703, whichpursuant to 35 U.S.C. §119(a) claims the benefit of earlier filing dateand right of priority to Korean Application No. 2003-0030271, filed onMay 13, 2003, the contents of all of which are hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for providing anMBMS (multimedia broadcast/multicast service) for UMTS (Universal MobileTelecommunication System) that supports the mobility of a terminal and,more particularly, a method and apparatus for informing a terminalregarding state information of MBMS in order to prevent the terminalfrom requesting a service that cannot be provided.

2. Description of the Related Art

A universal mobile telecommunication system (UMTS) is a European-type,third generation IMT-2000 mobile communication system that has evolvedfrom a European standard known as Global System for Mobilecommunications (GSM). UMTS is intended to provide an improved mobilecommunication service based upon a GSM core network and wideband codedivision multiple access (W-CDMA) wireless connection technology.

In December 1998, a Third Generation Partnership Project (3GPP) wasformed by the ETSI of Europe, the ARIB/TTC of Japan, the T1 of theUnited States, and the TTA of Korea. The 3GPP creates detailedspecifications of UMTS technology. In order to achieve rapid andefficient technical development of the UMTS, five technicalspecification groups (TSG) have been created within the 3GPP forstandardizing the UMTS by considering the independent nature of thenetwork elements and their operations.

Each TSG develops, approves, and manages the standard specificationwithin a related region. Among these groups, the radio access network(RAN) group (TSG-RAN) develops the standards for the functions,requirements, and interface of the UMTS terrestrial radio access network(UTRAN), which is a new radio access network for supporting W-CDMAaccess technology in the UMTS.

FIG. 1 illustrates an exemplary basic structure of a general UMTSnetwork. As shown in FIG. 1, the UMTS is roughly divided into a terminalor user equipment (UE) 10, a UTRAN 20, and a core network (CN) 30.

The UTRAN 20 includes one or more radio network sub-systems (RNS) 25.Each RNS 25 includes a radio network controller (RNC) 23 and a pluralityof Node-Bs (base stations) 21 managed by the RNC 23. The RNC 23 handlesthe assignment and management of radio resources and operates as anaccess point with respect to the core network 30.

The Node-Bs 21 receive information sent by the physical layer of theterminal 10 through an uplink and transmit data to the terminal 10through a downlink. The Node-Bs 21 operate as access points of the UTRAN20 for the terminal 10.

The UTRAN 20 constructs and maintains a radio access bearer (RAB) forcommunication between the terminal 10 and the core network 30. The corenetwork 30 requests end-to-end quality of service (QoS) requirementsfrom the RAB, and the RAB supports the QoS requirements the core network30 has set. Accordingly, by constructing and maintaining the RAB, theUTRAN 20 can satisfy the end-to-end QoS requirements.

The services provided to a specific terminal 10 are roughly divided intothe circuit switched (CS) services and the packet switched (PS)services. For example, a general voice conversation service is a circuitswitched service, while a Web browsing service via an Internetconnection is classified as a packet switched (PS) service.

For supporting circuit switched services, the RNCs 23 are connected tothe mobile switching center (MSC) 31 of the core network 30 and the MSC31 is connected to the gateway mobile switching center (GMSC) 33 thatmanages the connection with other networks. For supporting packetswitched services, the RNCs 23 are connected to the serving generalpacket radio service (GPRS) support node (SGSN) 35 and the gateway GPRSsupport node (GGSN) 37 of the core network 30. The SGSN 35 supports thepacket communications with the RNCs 23 and the GGSN 37 manages theconnection with other packet switched networks, such as the Internet.

FIG. 2 illustrates a structure of a radio interface protocol between theterminal 10 and the UTRAN 20 according to the 3GPP radio access networkstandards. As shown in FIG. 2, the radio interface protocol hashorizontal layers comprising a physical layer, a data link layer, and anetwork layer, and has vertical planes comprising a user plane (U-plane)for transmitting user data and a control plane (C-plane) fortransmitting control information.

The user plane is a region that handles traffic information with theuser, such as voice or Internet protocol (IP) packets. The control planeis a region that handles control information for an interface with anetwork, maintenance and management of a call, and the like.

The protocol layers in FIG. 2 can be divided into a first layer (L1), asecond layer (L2), and a third layer (L3) based on the three lowerlayers of an open system interconnection (OSI) standard model.

The first layer (L1), namely, the physical layer, provides aninformation transfer service to an upper layer by using various radiotransmission techniques. The physical layer is connected to an upperlayer called a medium access control (MAC) layer, via a transportchannel. The MAC layer and the physical layer exchange data via thetransport channel.

The second layer (L2) includes a MAC layer, a radio link control (RLC)layer, a broadcast/multicast control (BMC) layer, and a packet dataconvergence protocol (PDCP) layer.

The MAC layer handles mapping between logical channels and transportchannels and provides allocation of the MAC parameters for allocationand re-allocation of radio resources. The MAC layer is connected to anupper layer called the radio link control (RLC) layer, via a logicalchannel.

Various logical channels are provided according to the type ofinformation transmitted. In general, a control channel is used totransmit information of the control plane and a traffic channel is usedto transmit information of the user plane.

A logical channel may be a common channel or a dedicated channeldepending on whether the logical channel is shared. Logical channelsinclude a dedicated traffic channel (DTCH), a dedicated control channel(DCCH), a common traffic channel (CTCH), a common control channel(CCCH), a broadcast control channel (BCCH), and a paging control channel(PCCH). The BCCH provides information including information utilized bya terminal 10 to access a system. The PCCH is used by the UTRAN 20 toaccess a terminal 10.

The MAC layer is connected to the physical layer by transport channelsand can be divided into a MAC-b sub-layer, a MAC-d sub-layer, a MAC-c/shsub-layer, and a MAC-hs sub-layer according to the type of transportchannel being managed. The MAC-b sub-layer manages a BCH (BroadcastChannel), which is a transport channel handling the broadcasting ofsystem information. The MAC-c/sh sub-layer manages a common transportchannel, such as a forward access channel (FACH) or a downlink sharedchannel (DSCH), which is shared by a plurality of terminals. The MAC-dsub-layer manages a dedicated channel (DCH), which is a dedicatedtransport channel for a specific terminal 10. Accordingly, the MAC-dsublayer is located in a serving RNC (SRNC) that manages a correspondingterminal, and one MAC-d sublayer also exists in each terminal.

The RLC layer supports reliable data transmissions and performssegmentation and concatenation on a plurality of RLC service data units(SDUs) delivered from an upper layer. When the RLC layer receives theRLC SDUs from the upper layer, the RLC layer adjusts the size of eachRLC SDU in an appropriate manner based upon processing capacity and thencreates data units by adding header information thereto. The data units,called protocol data units (PDUs), are transferred to the MAC layer viaa logical channel. The RLC layer includes a RLC buffer for storing theRLC SDUs and/or the RLC PDUs.

The BMC layer schedules a cell broadcast (CB) message transferred fromthe core network and broadcasts the CB message to terminals 10positioned in a specific cell or cells.

The PDCP layer is located above the RLC layer. The PDCP layer is used totransmit network protocol data, such as the IPv4 or IPv6, effectively ona radio interface with a relatively small bandwidth. For this purpose,the PDCP layer reduces unnecessary control information used in a wirednetwork, a function called header compression.

The radio resource control (RRC) layer located at the lowest portion ofthe third layer (L3) is only defined in the control plane. The RRC layercontrols the transport channels and the physical channels in relation tosetup, reconfiguration, and the release or cancellation of the radiobearers (RBs). The RB signifies a service provided by the second layer(L2) for data transmission between the terminal 10 and the UTRAN 20. Ingeneral, the set up of the RB refers to the process of stipulating thecharacteristics of a protocol layer and a channel required for providinga specific data service, and setting the respective detailed parametersand operation methods.

The RRC state refers to whether there exists a logical connectionbetween the RRC of the terminal 10 and the RRC of the UTRAN 20. If thereis a connection, the terminal 10 is said to be in RRC connected state.If there is no connection, the terminal 10 is said to be in idle state.

Because an RRC connection exists for terminals 10 in RRC connectedstate, the UTRAN 20 can determine the existence of a particular terminalwithin the unit of cells, for example which cell the RRC connected stateterminal is in. Thus, the terminal 10 can be effectively controlled.

In contrast, the UTRAN 20 cannot determine the existence of a terminal10 in idle state. The existence of idle state terminals 10 can only bedetermined by the core network 30 to be within a region that is largerthan a cell, for example a location or a routing area. Therefore, theexistence of idle state terminals 10 is determined within large regions,and, in order to receive mobile communication services such as voice ordata, the idle state terminal must move or change into the RRC connectedstate.

The 3GPP system can provide multimedia broadcast multicast service(MBMS), which is a new type of service in Release 6. The 3GPP TSG SA(Service and System Aspect) defines various network elements and theirfunctions required for supporting MBMS services. A cell broadcastservice provided by the conventional Release 99 is limited to a servicein which text type short messages are broadcast to a certain area. TheMBMS service provided by Release 6 is a more advanced service thatmulticasts multimedia data to terminals (UEs) 10 that have subscribed tothe corresponding service in addition to broadcasting multimedia data.

The MBMS service is a downward-dedicated service that provides astreaming or background service to a plurality of terminals 10 by usinga common or dedicated downward channel. The MBMS service is divided intoa broadcast mode and a multicast mode.

The MBMS broadcast mode facilitates transmitting multimedia data toevery user located in a broadcast area, whereas the MBMS multicast modefacilitates transmitting multimedia data to a specific user grouplocated in a multicast area. The broadcast area signifies a broadcastservice available area and the multicast area signifies a multicastservice available area.

FIG. 3 illustrates a process of providing a particular MBMS service,referred to as service 1, by using multicast mode. A user desiring toreceive the MBMS service, for example UE1, first receives a serviceannouncement provided by a network at the terminal 10. The serviceannouncement provides the terminal 10 with a list of services to beprovided and related information. In addition, the user must receive aservice notification provided by the network. The service notificationprovides the terminal 10 with information related to the broadcast datato be transmitted.

If the user intends to receive the multicast mode MBMS service, the usersubscribes to a multicast subscription group. A multicast subscriptiongroup is a group of users who have completed a subscription procedure.Once a user has subscribed to the multicast subscription group, the usercan join a multicast group to receive a specific multicast service. Amulticast group is a group of users that receive a specific multicastservice. Joining a multicast group, also referred to as MBMS multicastactivation, involves merging with the multicast group that has users whowish to receive the specific multicast service. Accordingly, the usercan receive the specific multicast data by joining a multicast group,referred to as MBMS multicast activation. Each terminal 10 mayindividually subscribe to a multicast subscription group and join orleave a multicast group before, during, or any time after datatransmission.

While a particular MBMS service is in progress, one or more sessions forthat service may occur in sequence. When data to be transmitted for aparticular MBMS service is generated at the MBMS data source, the corenetwork 30 indicates the start of a session to the RNC 23. In contrast,when there is no further data to be transmitted for a particular MBMSservice, the core network 30 indicates a session stop to the RNC 23.

Between session start and session stop, data transmission for theparticular MBMS service is performed. Only those terminals 10 that havejoined a multicast group for the MBMS service may receive data thatduring the data transmission.

In the session start procedure, the UTRAN 20 that received the sessionstart from the core network 30 transmits an MBMS notification to theterminals 10. MBMS notification involves to UTRAN 20 informing theterminal 10 that transmission of data for a particular MBMS servicewithin a certain cell is impending.

The UTRAN 20 can use the MBMS notification procedure to perform acounting operation that determines the number of terminals 10 that wishto receive a particular MBMS service within a particular cell. Thecounting procedure is used to determine whether the radio bearer forproviding the particular MBMS service should be set aspoint-to-multipoint or point-to-point.

To select the MBMS radio bearer, the UTRAN 20 internally establishes athreshold value. After performing the counting function, the UTRAN 20may set a point-to-point MBMS radio bearer if the number of terminals 10existing within the corresponding cell is smaller than a threshold valueand may set a point-to-multipoint MBMS radio bearer if the number ofterminals existing within the corresponding cell is greater than orequal to the threshold value.

When a point-to-point radio bearer is set for a particular service, theterminals 10 wishing to receive the corresponding service are all in anRRC connected state. However, when a point-to-multipoint radio bearer isset for a particular service, all the terminals 10 wishing to receivethe corresponding service need not be in an RRC connected state sinceterminals in an idle state may also receive the point-to-multipointradio bearer.

In the related art, when a point-to-multipoint radio bearer is set for aparticular service within a particular cell, the UTRAN 20 may allow someterminals 10 to stay in RRC connected state based upon radio resourcemanaging conditions while requiring the remaining terminals to be inidle state. For example, when the UTRAN 20 receives an RRC connectionrequest message from the terminals 10 wishing to receive a particularservice, RRC connection setup messages are sent to a limited number ofterminals according to the radio resource managing conditions forcontrolling the reception of the corresponding service in RRC connectedstate. RRC connection reject messages are transmitted to the otherterminals 10 so that these terminals may receive the correspondingservice in idle state.

FIG. 4 illustrates a signal flow chart indicating successful RRCconnection setup according to the conventional art. After an MBMSsession start message is received from the core network 30 in step S50,the UTRAN 20 transmits an MBMS notification message to those terminals10 wishing to receive the corresponding MBMS service in step S52 toindicate that data transmission for the particular MBMS service isimpending.

Each terminal 10 that receives the MBMS notification message transmitsan RRC connection request message to the UTRAN 20 in step S54. The UTRAN20 considers the current condition of radio resources and determines, instep S56, which RRC connections should be granted with a limited numberof terminals 10 below a threshold value.

In step S58 the UTRAN 20 transmits RRC connection setup messages to theterminals selected for RRC connection. The terminals that receive theRRC connection setup message then transmit an RRC connection setupcomplete message to the UTRAN 20 in step S60. Upon successfullycompleting this procedure, an RRC connection exists between eachselected terminal 10 and the UTRAN 20 and each selected terminal is inRRC connected state. In step S62, the UTRAN 20 allows those terminalsnot selected for RRC connection that desire to receive the MBMS serviceto set up a point-to-multipoint MBMS bearer.

FIG. 5 illustrates a signal flow diagram showing unsuccessful RRCconnection setup according to the conventional art. After an MBMSsession start message is received from the core network 30 in step S50,the UTRAN 20 transmits an MBMS notification message to those terminals10 wishing to receive the corresponding MBMS service in step S52 toindicate that data transmission for the particular MBMS service isimpending.

Each terminal 10 that receives the MBMS notification transmits an RRCconnection request message to the UTRAN 20 in step S54. The UTRAN 20considers the current condition of radio resources and determines, instep S56, which RRC connections should be granted with a limited numberof terminals 10 below a threshold value.

As illustrated in FIG. 5, the UTRAN 20 determines that RRC connectionsshould not be granted for those terminals 10 that exceed the thresholdvalue, for example any terminal counted after the number of terminalsreached the threshold value. The UTRAN 20 transmits, in step S59, RRCconnection reject messages to those terminals 10 determined not torequire an RRC connection. The terminals 10 receiving an RRC connectionreject message are in idle state. In step S62, the UTRAN 20 allows thoseterminals 10 not selected for RRC connection that desire to receive theMBMS service to set up a point-to-multipoint MBMS bearer.

FIGS. 4 and 5 illustrate the procedure when there is at least oneterminal 10 that desires to receive a particular MBMS service. However,if there are no terminals 10 that desire to receive a particular MBMSservice as a result of the counting process, the UTRAN 20 does not setup a radio bearer and does not transmit MBMS data since setting up aradio bearer when there are no users who desire the service would wasteradio resources.

When data of an MBMS service is transmitted from the core network 30during one session of the MBMS service, the UTRAN 20 uses theestablished radio bearer to transmit the data. Upon receiving a sessionstop command from the core network, the established radio bearer isreleased by the UTRAN 20.

A terminal 10 that is receiving MBMS service within one cell may move toa different cell or a terminal may be powered on in a cell, therebycreating one of two situations depending upon whether the MBMS servicedata is also being transmitted to the cell.

The first situation occurs when the MBMS service data previouslyreceived by the terminal 10, or desired by a terminal that has beenpowered on, is being transmitted to the new cell in which the terminalresides. In order to allow the terminal 10 to receive the MBMS servicedata in the new cell, the UTRAN 20 informs the terminal 10 about theinformation related to the corresponding MBMS radio bearer within thatcell until a session stop for the corresponding MBMS service isreceived.

Through this procedure, the terminal 10 that has moved to a new cell mayreceive information of the MBMS radio bearer that is transmitted via acommon channel, such as the MCCH or BCCH, of the new cell in which theterminal now resides and the terminal may set up its parameters, orenvironment, such that the MBMS service can be continuously received.Also through this procedure, any terminal 10 that is powered on while asession of the MBMS service is in progress within a cell can receiveinformation of the MBMS radio bearer that is transmitted via a commoncontrol channel and establish its parameters in order to receive theMBMS service data.

The second situation occurs when the MBMS service data previouslyreceived by a terminal 10, or desired by a terminal that has beenpowered on, is not being transmitted to the new cell in which theterminal resides. This situation arises because there are no terminals10 in the new cell that receive the corresponding MBMS service prior tothe terminal moving into, or being powered on in, that cell. If theterminal 10 that moved into, or was powered on in, the new cell cannotreceive information about the radio bearer of the corresponding MBMSservice, the terminal sets up a connection with the UTRAN 20 andrequests that MBMS data be transmitted to the terminal.

Upon receiving a particular MBMS data transmission request from theterminal 10, the UTRAN 20 requests that the core network 30 transmit theMBMS service data. The UTRAN 20 then sets up an MBMS radio bearer forthe corresponding cell and begins transmitting the MBMS data receivedfrom the core network 30 to the terminal 10. The UTRAN 20 also transmitsthe information related to the MBMS radio bearer via a common controlchannel until that session is completed.

Through the two abovementioned methods, a terminal 10 is able to receivean MBMS service even after moving into a different cell or after beingpowered on. However, the UTRAN 20 does not inform the terminal 10 aboutthe state, or condition, of the particular MBMS service and the terminaloperates without any knowledge of the state of the particular MBMSservice. The terminal 10 may not operate properly if it requests datafrom the UTRAN 20 related to a particular MBMS service if thecorresponding MBMS service session ended before the terminal moved to,or was powered on in, the new cell or if the new cell is not part of theservice area.

Therefore, there is a need for a method and apparatus that facilitatesinforming a terminal regarding state information of MBMS in order toprevent the terminal from requesting a service that cannot be provided.The present invention addresses this and other needs.

SUMMARY OF THE INVENTION

The present invention is directed to a to a method and apparatus forproviding state information to a terminal regarding a service theterminal desires to receive but which may not be available.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described, the presentinvention is embodied in a mobile communication system and device thatfacilitates providing state information to a terminal regarding aservice which the terminal desires to receive. Specifically, a methodand apparatus is provided that allows the terminal to consider theavailability of a particular service before requesting a networkconnection related to the service when the terminal first begins tooperate in a cell.

In one aspect of the present invention, a method is provided for aterminal in radio communication with a network. The method includes aterminal subscribing to a particular service and operating for the firsttime in a cell in which the particular service is not being transmitted,receiving a control message from the network including an identificationand state information related to a service being provided in the celland comparing the identification of the provided service to theparticular service to which the terminal subscribes in order todetermine whether the service is available in the cell. The stateinformation related to the provided service includes informationindicating whether connection requests are being sought from terminalsor if the provided service is currently being transmitted.

It is contemplated that the terminal may be operating for the first timein a cell due to being powered on or having relocated from another cell.By informing the terminal of the identity of the service being provided,the terminal can determine whether the particular service to which theterminal subscribes is not being transmitted because the service is notavailable in the cell. The terminal utilizes the service identificationin the control message to determine if the service provided in the cellis the particular service to which the terminal subscribes.

If the service identification in the control message does not match theservice identification of the particular service to which the terminalsubscribes, the terminal determines that the particular service is notavailable in the cell and recognizes a “service not available” phase.The terminal will not waste radio resources by trying to initiate aconnection process with the network, for example by transmitting arequest message.

If the service identification in the control message matches the serviceidentification of the particular service to which the terminalsubscribes, the terminal determines that the particular service isavailable in the cell and recognizes a “service available” state. Theterminal transmits a request message to the network to request theparticular service.

Preferably the “service not available” state is a null phase in whichthere is either not an ongoing session of the particular service or thecell does not belong to the service area of the particular service.Preferably “service available” state is either a preparation phase, inwhich the network is currently performing a counting procedure to decidethe type of radio bearer to establish based on the number of terminalsin the cell that desire to receive the particular service, or ano-transmission state, in which there is no radio bearer establishedbecause there is no terminal in the cell that wants to receive theservice.

Preferably the connection process is associated with the particularservice, for example an MBMS service, and is initiated to obtain an RRCconnection between the terminal and network. Preferably control messageis an MBMS notification message and the request message is an RRCconnection request message.

In another aspect of the present invention, a method is provided for aterminal in radio communication with a network. The method includes aterminal subscribing to a particular service and operating for the firsttime in a cell, receiving a control message from the network includingan identification and state information related to a service beingprovided in the cell and comparing the identification of the providedservice to the particular service to which the terminal subscribes inorder to determine whether the particular service is available in thecell and, if the service is available, determine the connection processfor receiving the service. The state information related to the providedservice includes information indicating whether connection requests arebeing sought from terminals or if the provided service is currentlybeing transmitted.

It is contemplated that the terminal may be operating for the first timein a cell due to being powered on or having relocated from another cell.By informing the terminal of the identity of the service being provided,the terminal can determine whether the particular service to which theterminal subscribes is not being transmitted because the service is notavailable in the cell. The terminal utilizes the service identificationin the control message to determine if the service provided in the cellis the particular service to which the terminal subscribes.

The terminal utilizes the service identification in the control messageto recognize a null phase in which the particular service to which theterminal subscribes is not available in the cell because there is eithernot an ongoing session of the particular service or the cell does notbelong to the service area of the particular service. If the serviceidentification in the control message does not match the serviceidentification of the particular service to which the terminalsubscribes, the terminal recognizes the null phase. The terminal willnot waste radio resources by trying to initiate a connection processwith the network, for example by transmitting a request message.

If the service identification in the control message matches the serviceidentification of the particular service to which the terminalsubscribes, the terminal acts pursuant to the state information in thecontrol message to either transmit a connection request or establish aradio bearer. It is contemplated the state information of the controlmessage may indicate a preparation phase, a point-to-point state, apoint-to-multipoint state, and a no-transmission state.

In the preparation phase, the network is currently performing a countingprocedure to decide the type of radio bearer to establish based on thenumber of terminals that desire to receive the particular service n thecell. In the no-transmission state, there is no radio bearer establishedbecause there is no terminal in the cell that desires to receive theservice. The point-to-point state and point-to-multipoint state arestates in which the particular service is currently being transmittedand radio bearers are established.

If the point-to-point state is indicated, the terminal establishes apoint-to-point radio bearer in order to receive the particular service.If the point-to-multipoint state is indicated, the terminal establishesa point-to-multipoint radio bearer in order to receive the particularservice. Preferably the radio bearer is an RRC connection between theterminal and the network. If the preparation phase or theno-transmission state is indicated, the terminal transmits a requestmessage in order to receive the particular service.

Preferably the request message is an RRC connection request messageassociated with the particular service and the control message is anMBMS notification message. Preferably the service is an MBMS service.

In another aspect of the present invention, a method is provided for aterminal in radio communication with a network. The method includes aterminal subscribing to a particular service and operating for the firsttime in a cell, receiving a control message from the network including aservice ID, a transmission state indicator and a counting status relatedto a service being provided in the cell, comparing the serviceidentification of the provided service to the particular service towhich the terminal subscribes in order to recognize a first phase, asecond phase or a third phase, and determining whether to initiate aconnection procedure with the network and how the connection procedureis initiated based on the recognized phase. The service ID is theidentity of the service provided in the cell. The transmission stateindicator indicates whether the provided service is presently beingtransmitted. The counting status indicates whether a counting operationis being performed.

The terminal utilizes the service ID in the control message to recognizethe first phase, preferably a null phase in which the particular serviceto which the terminal subscribes is not available in the cell becausethere is either not an ongoing session of the particular service or thecell does not belong to the service area of the particular service. Ifthe service ID in the control message does not match the serviceidentification of the particular service to which the terminalsubscribes, the terminal recognizes the first phase. The terminal willnot waste radio resources by trying to initiate a connection processwith the network, for example by transmitting a request message.

If the service ID in the control message matches the serviceidentification of the particular service to which the terminalsubscribes, the terminal recognizes that either the second phase or thethird phase exists. The terminal initiates a connection procedure.

Preferably the second phase is a preparation phase in which the networkis currently performing a counting procedure to decide the type of radiobearer to establish based on the number of terminals that want toreceive the particular service in the cell. Preferably that third phaseincludes a no-transmission state, a point-to-point state and apoint-to-multipoint state indicated by the transmission state indicator.The no-transmission state is a state in which in which there is no radiobearer established because there is no terminal in the cell that wantsto receive the service. The point-to-point state and point-to-multipointstate are states in which the particular service is currently beingtransmitted and radio bearers are established.

The terminal utilizes the transmission state indicator and countingstatus in the control message to determine whether to initiate aconnection procedure by transmitting a connection request or toestablish a radio bearer. If the counting status indicates that acounting procedure is being performed or the transmission stateindicator indicates that the provided service is not being transmitted,the terminal initiates a connection procedure by transmitting aconnection request. If the transmission state indicator indicates thatthe provided service is being transmitted, the terminal establishes apoint-to-point or point-to-multipoint radio bearer based on the type oftransmission indicated by the transmission state indicator.

In another aspect of the present invention, a method is provided for anetwork in radio communication with a plurality of terminals. The methodincludes receiving a service session start indication, determining thenumber of terminals in a cell that presently subscribe to the serviceand transmitting a control message including a service identificationand state information to solicit a connection request if there are noterminals that presently subscribe to the service.

The service session start indication is preferably received from thecore network and is related to an MBMS service. Upon receiving thesession start indication, a counting operation is performed to determineif any terminals presently subscribe to the service.

After the counting operation is done, a control message, for example anMBMS notification message, is transmitted to the terminals. The controlmessage includes an identification of the service. If there are noterminals presently subscribing to the service, the control message alsoincludes state information associated with soliciting a connectionrequest from at least one of the terminals. The state informationfurther includes a transmission state indicator which indicates either apreparation phase or a no-transmission state.

It is contemplated that the method may include transmitting a controlmessage including a transmission state indicator which indicates a typeof radio bearer established if there is at least one terminal thatpresently subscribes to the service. The transmission state indicatormay indicate either point-to-multipoint radio bearer or a point-to-pointradio bearer was established based on the number of terminals presentlysubscribing to the service.

It is further contemplated that the method may include receiving aservice session stop indication and entering a null phase. The nullphase may include releasing any established radio bearers and haltingtransmission of the control message including identification and stateinformation related to a service.

It is also contemplated that the method may include detecting a terminalnewly introduced into the cell and providing a control message to informthe terminal of the state of the service. The control message includesstate information associated with soliciting a connection request fromthe newly introduced terminal if there are no other terminals presentlysubscribing to the service and a transmission state indicator indicatingthe type of radio bearer established with the newly introduced terminalif there is at least one other terminal presently subscribing to theservice.

In another aspect of the present invention, a terminal is provided forradio communication with a network. The terminal includes a receiver, atransmitter, a display, a memory unit and a processing unit.

The receiver receives a control message including a serviceidentification and service state information associated with a serviceprovided by the network when the terminal is first introduced into acell. The transmitter initiates a network connection process associatedwith the service by transmitting a connection request to the network.The display conveys information to a user. The memory unit storesinformation related to network connections and the user service. Theprocessing unit performs the methods of the present invention todetermine whether to initiate a connection process with the networkbased on the service identification and service state information in thecontrol message.

In another aspect of the present invention, a network is provided forradio communication with a plurality of terminals. The terminal includesa receiver, a transmitter, a storage unit, and a controller.

The receiver receives connection requests from terminals in a cellsubscribing to a service. The transmitter transmits a control message tothe terminals in the cell. The storage unit stores information relatedto network connections, the user service and the capability of theterminals to provide feedback information associated with the service.The controller performs the methods of the present invention to receivea service start indication from the core network, determine the numberof terminals in the cell that presently subscribe to the service, send acontrol message to the terminals including a service identification andservice state information that either solicits a connection request fromat least one terminal or indicates a type of radio bearer establishedbased on the number of terminals presently subscribing to the service,and enter a null phase upon receiving a service stop indication from thecore network.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objects and advantages of the invention may be realizedand attained as particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. Features, elements, and aspects of the invention that arereferenced by the same numerals in different figures represent the same,equivalent, or similar features, elements, or aspects in accordance withone or more embodiments.

FIG. 1 illustrates a network structure of a general 3GPP UMTS system.

FIG. 2 illustrates an exemplary basic structure of a general UMTSnetwork.

FIG. 3 illustrates an exemplary timeline for a conventional art UMTSnetwork providing a particular MBMS service.

FIG. 4 illustrates the conventional art procedure when the UTRAN acceptsthe RRC connection request of a terminal.

FIG. 5 illustrates the conventional art procedure when the UTRAN rejectsthe RRC connection request of a terminal.

FIG. 6 illustrates the transition of service provision states accordingto the a first embodiment of the present invention.

FIG. 7 illustrates a timeline for providing MBMS service according to asecond embodiment the present invention.

FIG. 8 illustrates a method for a network providing an MBMS serviceaccording to one embodiment of the present invention.

FIG. 9 illustrates a method for a terminal receiving an MBMS serviceaccording to one embodiment of the present invention.

FIG. 10 illustrates a terminal for receiving an MBMS service accordingto one embodiment of the present invention.

FIG. 11 illustrates a network for providing an MBMS service according toone embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a to a method and apparatus forproviding state information to a terminal regarding a service theterminal desires to receive in a new cell in which the terminal firstoperates such that the terminal may determine if the service isavailable and the process for receiving the service. Although thepresent invention is illustrated with respect to a mobile communicationsystem such as a UMTS developed by the 3GPP, and specifically an RRCconnection associated with an MBMS user service, it is contemplated thatthe methods and apparatus described herein may also be applied to acommunication system operating under similar and/or different standardswhen it is desired to provide information to a terminal when it firstoperates in a new cell.

The present invention provides a communication system that supportsterminal mobility and effectively utilizes radio resources to provide aparticular service to a terminal 400 by having the system inform theterminal regarding the state, or condition, of the particular service.In a wireless radio system that transmits a broadcast and/or multicastservice to a plurality of terminals 400 via a downlink channel, theUTRAN 520 informs terminals of the state of a particular broadcastand/or multicast service.

Information regarding the service state, or condition, of the UTRAN 520that may be provided to a terminal 400 include the UTRAN preparing datatransmission of a corresponding service, the UTRAN transmitting the dataof the corresponding service using a point-to-point radio bearer or apoint-to-multipoint radio bearer, the UTRAN not transmitting the data ofthe corresponding service, but waiting for a request for the data of thecorresponding service from a terminal, and the location region of theUTRAN is not within the service region or the session of thecorresponding service is not in progress. By transmitting the state ofthe particular service, problems associated with a terminal 400unnecessarily requesting service data from the UTRAN 520 when the UTRANis not operating in session or its location is not within a serviceregion are minimized.

In a first embodiment of the present invention, the UTRAN 520 operationsfor a particular broadcast and/or multicast service are divided intofive of states and managed. FIG. 7 illustrates transitions between thefive states.

The first state is a null (NULL) state 101, in which there is either noongoing session for the MBMS service or the cell does not belong to theservice area of the service. This is the basic state of the UTRAN 520,which transitions to a second state 102 upon receiving a session startmessage from the core network 30. The terminal 400 does not requestservice delivery from the UTRAN 520 in the NULL state.

The second state is a preparation (PR) state 102 in which the UTRAN 520is in a state of preparing or setting up the radio environment uponreceiving a service session start notification from the core network 30.This state starts when UTRAN 520 receives the service session start fromthe core network 30 and continues until the UTRAN informs the terminals400 of the radio bearer that was determined for use within the cell, orthat no radio bearer was setup.

In the PR state 102, the UTRAN 520 transmits notification to terminals400 regarding the incoming service and performs a counting procedure todetermine the type of radio bearer. The UTRAN 520 decides whether to setup a point-to-multipoint radio bearer, a point-to-point radio bearer orno radio bearer based on the number of terminals 400 that desire toreceive the service in the cell.

Depending upon the determination made in the PR state 102, the UTRAN 520transitions to one of three states. A point-to-point (PTP) state 103 isentered if a point-to-point radio bearer is set. A point-to-multipoint(PTM) state 104 is entered if a point-to-multipoint radio bearer is set.A no-transmission (NT) state 105 is entered if no radio bearer is setradio.

A point-to-multipoint radio bearer is set up if the number of terminals400 that desire to receive the service is greater than or equal to athreshold value and a point-to-point radio bearer is set up if thenumber of terminals that desire to receive the service is less than thethreshold value. If no radio bearer is set up because there are noterminals 400 desiring to receive the service, the terminals are soinformed.

In the PTP state 103, the UTRAN 520 receives service data transmittedfrom the core network 30 and transmits the data to the terminals 400 byusing the point-to-point radio bearer. The UTRAN 520 may change theradio bearer to a point-to-multipoint radio bearer when the number ofterminals 400 requesting the service exceeds the threshold value andtransition to the PTM state 104 after informing the terminals 400. TheUTRAN 520 may release, or cancel, the point-to-point radio bearer whenthere are no users within the cell and transition to the NT 105 stateafter informing the terminals 400. When the MBMS service session iscomplete, the UTRAN 520 cancels the point-to-point radio bearer andtransitions to the NULL state 101.

In the PTM state 104, the UTRAN 520 receives service data transmittedfrom the core network 30 and transmits the data to the terminals 400 byusing the point-to-multipoint radio bearer. The UTRAN 520 may change theradio bearer to a point-to-point radio bearer when the number ofterminals 400 requesting the service is below the threshold value andtransition to the PTP state 103 after informing the terminals 400. TheUTRAN 520 may release, or cancel, the point-to-multipoint radio bearerwhen there are no users within the cell and transition to the NT state105 state after informing the terminals 400. When the MBMS servicesession is complete, the UTRAN 520 cancels the point-to-multipoint radiobearer and transitions to the NULL state 101.

In the NT state 105, there is radio bearer set up and the UTRAN 520 doesnot transmit service data because there is no terminal 400 that desiresto receive the service within the cell although the session of thecorresponding service has begun. The UTRAN 520 waits for a service datatransmission request from one or more terminals 400.

If the UTRAN 520 receives service data transmission requests from anumber of terminals 400 that is below the threshold value, apoint-to-point radio bearer is set up and transition to the PTP state103 occurs after informing the terminals. If the UTRAN 520 receivesservice data transmission requests from a number of terminals 400 thatis greater than or equal to the threshold, a point-to-multipoint radiobearer is set up and transition to the PTM state 104 occurs afterinforming the terminals. When the MBMS service session is complete, theUTRAN 520 transitions to the NULL state 101.

Table 1 illustrates the types of information transmitted in each stateto inform the terminals 400 of the current state of the UTRAN 520 in thefirst embodiment of the present invention.

In Table 1, “Yes” and “No” indicate whether UTRAN 520 transmits thecorresponding data in each state. To allow a terminal 400 within thecorresponding cell to receive the above-identified information, theUTRAN 520 periodically transmits the information via a common controlchannel, such as the MCCH or BCCH.

TABLE 1 NULL PR PTM PTP NT state state state state state Service NO YESYES YES YES ID Session NO YES YES YES YES Ongoing Bearer NO NO YES YESYES Type (PTM) (PTP) (NT) State NO YES YES YES YES Information

“Service ID” is a unique identity for discriminating each MBMS service.“Session ongoing” indicates whether a current session is in progress.“Bearer type” indicates the type of radio bearer set up by the system,for example whether the radio bearer is point-to-point,point-to-multipoint, or no radio bearer is set. “State information”indicates the current state of the UTRAN 520, which may be inferred fromthe “Session ongoing” information and “Bearer type” information.Therefore, the UTRAN 520 may not transmit “Session ongoing” information.

In order for a terminal 400 in mobility to determine the state of theUTRAN 520 in the first embodiment of the invention, the terminal firstchecks whether there is a “Service ID” among those that are received viaa common control channel that matches the service the terminal desiresto receive. If the terminal 400 cannot find the corresponding “ServiceID,” the terminal recognizes the NULL state for that particular service.If the terminal 400 finds the corresponding “Service ID,” the terminalutilizes the “State Information” of the corresponding service todetermine the state of the system.

Since the UTRAN 520 may not transmit “State Information,” the terminal400 may use the “Session Ongoing” information and the “Bearer type”information to determine the state of the UTRAN 520 for thecorresponding service. After determining the state of the system, theterminal 400 operates in the accordance with the determined systemstate.

If the NULL state 101 is recognized, the terminal 400 determines thateither the cell is not within a service region or a session of thecorresponding service is not ongoing. The terminal 400 does not requestthe UTRAN 520 to transmit data of the service.

If the PR 102 state is recognized, the terminal 400 operates accordingto the messages transmitted via a common control channel. The terminal400 can receive service notification transmitted by the UTRAN 520. Ifthe UTRAN 520 is performing a counting procedure, the terminal 400informs the UTRAN that it wishes to receive transmission of the service.

If the PTP state 103 is recognized, the terminal 400 obtains thepoint-to-point radio bearer information that is transmitted via thecommon control channel. The terminal 400 sets up its environment andreceives the service data transmitted by the UTRAN 520.

If the PTM state 104 is recognized, the terminal 400 obtains thepoint-to-multipoint radio bearer information that is transmitted via thecommon control channel. The terminal 400 sets up its environment andreceives the service data transmitted by the UTRAN 520.

If the NT state 105 is recognized, the terminal 400 requests the UTRAN520 to transmit the corresponding MBMS service data. In the NT state105, the UTRAN 520 does not transmit the corresponding MBMS service datawithin the location region because there are no terminals 400 withincell wishing to receive the MBMS service. Therefore, the terminal 400must inform the UTRAN 520 that it desires to receive data of thecorresponding service.

The terminal 400 sends a message requesting data transmission of thecorresponding service including an identity of the service desired tothe UTRAN 520. The UTRAN 520 then indicates the radio bearer informationto the terminal 400 and the terminal sets up its environment accordingto the radio bearer information to receive the service data.

In a second embodiment of the present invention, UTRAN 520 operationsfor a particular broadcast and/or multicast service are divided intothree phases. FIG. 7 illustrates a timeline of an MBMS service inaccordance with the second embodiment of the present invention.

A cell stays in phase 1 if there is no ongoing session for the MBMSservice or if the cell does not belong to the service area of theservice. During phase 1, the UTRAN 520 is not involved in the MBMSservice. A terminal 10 that has joined an MBMS service may regularly tryto receive MBMS status information broadcast in the cell. The terminal10 does not request service delivery from the UTRAN 520.

Phase 2 starts when the UTRAN 520 receives the MBMS session start fromthe CN 30. Phase 2 ends when the UTRAN 520 initially sets up MBMS radiobearers for the session or decides not to set up an MBMS radio bearer ina cell.

In phase 2, the UTRAN 520 transmits notification to the terminals 10regarding the incoming service and performs a counting procedure todetermine the type of MBMS radio bearer to set up. The UTRAN 520 decideswhether to set up a point-to-multipoint radio bearer, a point-to-pointradio bearer or no radio bearer based on the number of terminals 10 thatdesire to receive the service in the cell. A terminal 10 that has joinedan MBMS service utilizes an RRC message on MCCH to request the service.

Phase 3 starts after initial MBMS radio bearer setup and ends when theUTRAN 520 receives the MBMS session stop from CN 30. In phase 3, theUTRAN 520 transmits the data for the MBMS service received from CN 30using, if any, the established radio bearer. If there is no radio bearerset-up, the UTRAN 520 waits for a service delivery request from aterminal 10. Recounting and radio bearer reconfiguration can beperformed during this phase.

The behavior of the UTRAN 520 in phase 3 can be divided into threestates; a no-transmission state, a point-to-point transmission state,and a point-to-multipoint transmission state. Each cell has one of thethree states. With the variation of the number of terminals 10, thestate of a cell can transition between three states. The UTRAN 520 maybroadcast those states to the terminals 10.

In the no-transmission state of a cell, there is no established radiobearer because there is no terminal 10 that desires to receive theservice. An MBMS-joined terminal 10 in idle mode that moves into a cellhaving this state requests service delivery from the UTRAN 520 bytransmitting a request message.

In the point-to-point state of a cell, a point-to-point radio bearer isestablished. A terminal 10 that has joined an MBMS service can receiveMBMS data over a point-to-point radio bearer if there is MBMS data toreceive.

In the point-to-multipoint state of a cell, a point-to-multipoint radiobearer is established. A terminal 10 that has joined an MBMS service canreceive MBMS data over a point-to-multipoint radio bearer if there isMBMS data to receive.

Table 2 illustrates the types of information transmitted in each phaseof MBMS in the second embodiment of the present invention to inform theterminals 400 of the current state of the UTRAN 520. In Table 2, “Yes”indicates that the UTRAN 520 transmits the data and the possible statesare indicated, while “No” indicates that the UTRAN 520 does not transmitthe data.

“Service ID” is a unique identity for the particular service provided.“Transmission State” indicates the state of the cell in the phase 3, forexample what type (PTP, PTM or None) of transmission is in progress.“Counting” indicates whether the UTRAN 520 is currently performing acounting procedure. If “On” is indicated by “Counting, a terminal 400transmits a request message to receive the service.

TABLE 2 NULL PR PTM PTP NT Phase Phase state state state Service No YesYes Yes Yes ID Transmission No No Yes Yes Yes State (PTM) (PTP) (NONE)Counting No Yes Yes Yes Yes (Off/On) (Off/On) (Off/On) (Off/On)

In order for a terminal 400 in mobility to determine the state of theUTRAN 520 in the second embodiment of the invention, the terminal firstdetermines if a “Service ID” received via a common control channelmatches the service identification for the service that the terminaldesires to receive. A terminal 400 in mobility is a terminal, forexample, that moved into a new cell or had its power newly turned on.

If the “Service ID” does not match the service identification of thedesired service, the terminal 400 recognizes phase 1 for that particularservice. The terminal 400 determines that the cell is either not withina service region or that a session of the corresponding service is notongoing, and does not request the UTRAN 520 to transmit data of theservice.

If the “Service ID” matches the service identification of the desiredservice, the terminal 400 utilizes the “Transmission State” of thecorresponding service to determine the state of the system. Determiningthe state of the system allows the terminal 400 to either startreconfiguration of the radio bearer or transmit a service request to theUTRAN 520.

If the UTRAN 520 is in phase 2, the terminal 400 operates according tothe messages transmitted via a common control channel. The terminal 400can receive service notification transmitted by the UTRAN 520. If“Counting” indicates “On,” a count is in progress and the terminal 400informs the UTRAN 520 that it desires to receive transmission of theservice by transmitting a service request to the UTRAN.

If the UTRAN is in phase 3, the terminal 400 utilizes the “TransmissionState” to determine which type of radio bearer, if any, to establish. If“Transmission State” indicates PTP state, the terminal 400 establishes apoint-to-point radio bearer. If “Transmission State” indicates PTMstate, the terminal 400 establishes a point-to-multipoint radio bearer.If “Transmission State” indicates NONE, the terminal 400 sends a servicerequest to the UTRAN 520.

FIG. 8 illustrates a method 200 for a network providing an MBMS serviceaccording to one embodiment of the present invention. The method 200includes receiving a session start indication (S202), initiating acounting process (S204) to determine the number of terminals 400 thatsubscribe to the service, determining based on the count (S206) whetherto set a connection required indicator (S208) or establish a radiobearer (S210), transmitting a control message including the connectionrequired indicator, service ID and state information, and upon receivinga session stop indication (S214), entering a NULL phase (S216).

Upon receiving a session start indication for a particular service fromthe CN 30 in step S202, the UTRAN 520 transitions from the NULL phase101 to the PR phase 102. A count of terminals 400 presently subscribingto the particular service, for example an MBMS service, is initiated instep S204 and the results of the count are utilized in step S206 todetermine whether a radio bearer is established or connection requestsare solicited from terminals 400 in the cell.

If there are no terminals 400 in the cell presently subscribing to theservice, an RRC connection-required indicator is set in step S208 andthe UTRAN 520 transitions to the NT state 105. If there is at least oneterminal 400 in the cell subscribing to the service, a radio bearer,such as an RRC connection between the UTRAN 520 and at least oneterminal, is established in step S210 based on the number of subscribingterminals 400 and the UTRAN 520 transitions to the PTP state 103 or thePTM state 104.

A control message, such as an MBMS notification message, is transmittedto the terminals 400 in the cell in step S212. The control messageincludes the service ID of the particular service, theconnection-required indicator and state information associated with theparticular service.

If it is determined in step S214 that a session stop indication wasreceived, the UTRAN 520 transitions to the NULL phase 101 in step S216.All established radio bearers are released, the connection-requiredindicator is reset and the service ID is no longer included in thecontrol message.

The method 200 illustrated in FIG. 8 may also include the detection of anewly introduced terminal 400 in the cell. Upon detecting a newlyintroduced terminal 400, the UTRAN 520 either establishes a radio bearerwith the terminal or sets an RRC connection-required indicator. If thereare other terminals 400 presently subscribing to the service, a radiobearer is established. If there are no other terminals 400 presentlysubscribing to the service, the connection-required indicator is set.

FIG. 9 illustrates a method 300 for a terminal receiving an MBMS serviceaccording to one embodiment of the present invention. The method 300includes a terminal 400 being newly introduced in a cell (S302),receiving a control message including a connection required indicator,service ID and state information (S304), determining whether a desiredservice is available (S306) and, if the service is available,determining whether the service is being transmitted (S310) in order toeither send a service request (S312) or establish a radio bearer (S314).If the service is not available, the terminal enters a NULL phase 101(S308)

A terminal 400 is newly introduced in a cell in step S302, for exampleby moving to a new cell or being powered up in the cell. The terminal400 receives a control message, such as an MBMS notification message,from the UTRAN 520 in step S304. The control message includes theservice ID of a particular service provided in the cell, aconnection-required indicator and state information associated with theparticular service.

The terminal 400 compares the service ID in the control message to theidentification of the desired service in step S306 to determine if thedesired service, for example an MBMS service, is available in the cell.If the service ID in the control message does not match theidentification of the desired service, the desired service is notpresently available in the cell. If the service ID in the controlmessage matches the identification of the desired service, the desiredservice is available in the cell.

If the desired service is not available in the cell, the terminal 400recognizes a NULL phase 101 for the desired service in step S308. Theterminal 400 does not request the service from the UTRAN 520.

If the service ID in the control message matches the identification ofthe desired service, the terminal 400 recognizes that either the PRphase 102, the PTP state 102, the PTM state 103 or the NT state 105exists for the desired service. The terminal 400 utilizes the stateinformation and connection-required indicator in the control message todetermine, in step S310, whether the service is presently beingtransmitted in the cell.

If the service in not presently being transmitted, the terminalrecognizes that the NT state 105 exists for the service and transmits arequest message to the UTRAN 520 in step S312. The request message ispreferably associated with the service, for example an RRC connectionrequest message.

If the service is being transmitted, the terminal establishes a radiobearer, for example an RRC connection between the terminal 400 and UTRAN520, to receive the service in step S314. The radio bearer is apoint-to-point radio bearer if the PTP state 103 exists and apoint-to-multipoint radio bearer if the PTM state 104 exists.

FIG. 10 illustrates a block diagram of a terminal 400 according to oneembodiment of the present invention. The terminal 400 comprises aprocessor or digital signal processor 410, RF module 435, powermanagement module 405, antenna 440, battery 455, display 415, keypad420, memory 430, SIM card 425 (which may be optional), speaker 445 andmicrophone 450.

A user enters instructional information, such as a telephone number, forexample, by pushing the buttons of a keypad 420 or by voice activationusing the microphone 450. The processor 410 receives and processes theinstructional information to perform the appropriate function, such asto dial the telephone number. Operational data may be retrieved from theSubscriber Identity Module (SIM) card 425 or the memory module 430 toperform the function. Furthermore, the processor 410 may display theinstructional and operational information on the display 415 for theuser's reference and convenience. Moreover, the processor 410 is adaptedto perform the method illustrated in FIG. 9.

The processor 410 issues instructional information to the RF module 435,to initiate communication, for example, transmit radio signalscomprising voice communication data or transmit an RRC connectionrequest message as described herein. The RF module 435 comprises areceiver and a transmitter to receive and transmit radio signals. Anantenna 440 facilitates the transmission and reception of radio signals.Upon receiving radio signals such as an MBMS notification message fromthe network as described herein, the RF module 435 may forward andconvert the signals to baseband frequency for processing by theprocessor 412. The processed signals may also be transformed intoaudible or readable information outputted via the speaker 445, forexample if the radio signals are an incoming phone call.

FIG. 11 illustrates a block diagram of a UTRAN 520 according to thepreferred embodiment of the present invention. The UTRAN 520 includesone or more radio network sub-systems (RNS) 525. Each RNS 525 includes aradio network controller (RNC) 523 and a plurality of Node-Bs (basestations) 521 managed by the RNC. The RNC 523 handles the assignment andmanagement of radio resources and operates as an access point withrespect to the core network 30. Furthermore, the RNC 523 is adapted toperform the method illustrated in FIG. 8.

The Node-Bs 521 receive information sent by the physical layer of theterminal 410 through an uplink, and transmit data to the terminalthrough a downlink. The Node-Bs 521 operate as access points, or as atransmitter and receiver, of the UTRAN 520 for the terminal 410.

In the related art, with regards to a particular MBMS service, aterminal 10 cannot know the state of the cell in which it is located.According to the present invention, the system informs a terminal 400 ofits state for the particular MBMS service and the terminal operates inaccordance with this state information of the system. Therefore,unnecessary operations of the terminal 400 can be prevented andunnecessary signaling and waste of radio resources can be minimized.

For a terminal 400 that receives a particular service, the presentinvention provides a communication system wherein the terminal receives,state information associated with the particular service from thesystem. In particular, for a terminal 400 that receives a broadcastand/or multicast service via a downlink channel, the present inventionprovides a system wherein the terminal receives state informationassociated with a particular broadcast and/or multicast service that theterminal desires to receive from the UTRAN 520 within a location region.When the terminal 400 wishes to receive a particular broadcast and/ormulticast service from a new location region into which the terminal hasmoved, the terminal determines the UTRAN 520 state and operatesaccordingly.

It will be apparent to one skilled in the art that the preferredembodiments of the present invention can be readily implemented using,for example, the processor 410 or other data or digital processingdevice, either alone or in combination with external support logic.

Although the present invention is described in the context of mobilecommunication, the present invention may also be used in any wirelesscommunication systems using mobile devices, such as PDAs and laptopcomputers equipped with wireless communication capabilities. Moreover,the use of certain terms to describe the present invention should notlimit the scope of the present invention to certain type of wirelesscommunication system, such as UMTS. The present invention is alsoapplicable to other wireless communication systems using different airinterfaces and/or physical layers, for example, TDMA, CDMA, FDMA, WCDMA,etc.

The preferred embodiments may be implemented as a method, apparatus orarticle of manufacture using standard programming and/or engineeringtechniques to produce software, firmware, hardware, or any combinationthereof. The term “article of manufacture” as used herein refers to codeor logic implemented in hardware logic (e.g., an integrated circuitchip, Field Programmable Gate Array (FPGA), Application SpecificIntegrated Circuit (ASIC), etc.) or a computer readable medium (e.g.,magnetic storage medium (e.g., hard disk drives, floppy disks, tape,etc.), optical storage (CD-ROMs, optical disks, etc.), volatile andnon-volatile memory devices (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs,SRAMs, firmware, programmable logic, etc.). Code in the computerreadable medium is accessed and executed by a processor. The code inwhich preferred embodiments are implemented may further be accessiblethrough a transmission media or from a file server over a network. Insuch cases, the article of manufacture in which the code is implementedmay comprise a transmission media, such as a network transmission line,wireless transmission media, signals propagating through space, radiowaves, infrared signals, etc. Of course, those skilled in the art willrecognize that many modifications may be made to this configurationwithout departing from the scope of the present invention, and that thearticle of manufacture may comprise any information bearing medium knownin the art.

The logic implementation shown in the figures described specificoperations as occurring in a particular order. In alternativeimplementations, certain of the logic operations may be performed in adifferent order, modified or removed and still implement preferredembodiments of the present invention. Moreover, steps may be added tothe above described logic and still conform to implementations of theinvention.

The foregoing embodiments and advantages are merely exemplary and arenot to be construed as limiting the present invention. The presentteaching can be readily applied to other types of apparatuses. Thedescription of the present invention is intended to be illustrative, andnot to limit the scope of the claims. Many alternatives, modifications,and variations will be apparent to those skilled in the art. In theclaims, means-plus-function clauses are intended to cover the structuredescribed herein as performing the recited function and not onlystructural equivalents but also equivalent structures.

1. A method of communicating with a network in a wireless communicationsystem, the method comprising: receiving, by a terminal, a serviceidentifier for identifying a multimedia broadcast/multicast service(MBMS) service provided by a network; receiving, by the terminal, aparameter from the network for indicating a state of the MBMS service,wherein the state is one of a point-to-multipoint state, apoint-to-point state and a no-transmission state; requesting, by theterminal, transmission of data of the MBMS service from the network ifthe service identifier identifies the MBMS service and the parameterindicates the no-transmission state; and receiving, by the terminal, thedata of the MBMS service if the parameter indicates thepoint-to-multipoint state; wherein the service identifier and theparameter are received through a MBMS control channel (MCCH) or abroadcast control channel (BCCH), wherein requesting transmission of thedata of the MBMS service, by the terminal, comprises transmitting aRadio Resource Control (RRC) connection request message to the network,and wherein the method is performed when the terminal is in phase 3,which starts after initial MBMS radio bearer set-up and ends when thenetwork receives a MBMS session stop indication from a core network. 2.The method of claim 1, wherein a current state of the MBMS service for aparticular cell can transition to another state according to a variationin the number of terminals in that particular cell.
 3. A method ofcommunicating with terminals in a wireless communication system, themethod comprising: performing, by a network, a counting procedure forcounting a number of terminals that subscribed to a multimediabroadcast/multicast service (MBMS) service upon the network receiving asession start indication of the MBMS service from a core network;determining, by the network, a state of the MBMS service based on thecounted number of terminals, wherein the state is one of apoint-to-multipoint state, a point-to-point state and a no-transmissionstate; and transmitting, by the network, a service identifier foridentifying the MBMS service provided by the network, and a parameterindicating the determined state of the MBMS service; setting, by thenetwork, the parameter to the no-transmission state if there are noterminals subscribed to the MBMS service, wherein the service identifierand the parameter are transmitted through a MBMS control channel (MCCH)or a broadcast control channel (BCCH), wherein network operations forthe MBMS service comprise: a first phase during which the network is notinvolved with the MBMS service, if there is no ongoing session for theMBMS service, or if the terminal does not belong to a service area ofthe MBMS service; a second phase during which the network transmits anotification to the terminal regarding the MBMS service and performs thecounting procedure to determine a type of MBMS radio bearer that is tobe set up; and a third phase during which the network transmits data ofthe MBMS service; wherein the third phase starts after initial MBMSradio bearer setup and ends when the network receives an MBMS sessionstop from a core network, and wherein the third phase comprises thepoint-to-multipoint state, the point-to-point state, and theno-transmission state.
 4. The method of claim 3, wherein a current stateof the MBMS service for a particular cell can transition to anotherstate according to a variation in the number of terminals in thatparticular cell.